People in this country are too rattled, and there is too much at stake. Big talk about "shooting up the school" is headed in the same direction as bomb jokes at the airport.

Regrettably, it can take a little time for this realization to sink into the human brain in general, and — no offense, I'm just talking in statistical terms here — into the brain of the adolescent male in particular.

This isn't to say that most kids would even dream of doing something so dumb and dangerous as to threaten a shooting.

But enough "copycat" threats have been leveled in the wake of the Feb. 14 Parkland, Fla., massacre to make me wonder whether parents need to add yet another entry to the exhaustive list of sober "talks" they need to have with their kids. This one: Foolish Gun Talk Can Screw Up Your Life.

On Sunday, a 15-year-old student was arrested in Weatherford for posting a threat on Snapchat in which he said he would "shoot up" a local high school on the following day. The kid told sheriff's officials it was a joke. Two 15-year-old Granbury boys were arrested Friday after making a social media threat against their school.

If cases like these have ever been handled with a call to the parents and a good talking-to, they aren't now: These kids are now being held in juvenile detention centers, facing felony charges of making terroristic threats.

It's teens who are the most pointedly affected right now: by the Parkland shooting itself, and by an evolving sense of activism, and for some, by a powerful temptation to make stupid and irreversible copycat threats. Telling authorities they didn't mean it won't buy anybody a pass, because the authorities cannot afford to make the wrong call.

I'm not talking here about kids who are seriously troubled and bent on violence. The 19-year-old Parkland shooter's rampage didn't surprise the people who knew him personally — he had been telegraphing his plan for years.

But it's precisely because so many observers and institutions failed to stop him that even a minor margin for "red flag" tolerance has been erased. If an otherwise "good kid" makes a dumb shooting-up-the-school joke right now, few will care about his record. They'll care about what he (or she) said.

A South Carolina ninth-grader was arrested Feb. 15, after he posted a Snapchat photo warning, "Round 2 of Florida Tomorrow." He told authorities he thought he was being funny.

An 11-year-old Florida girl wrote a threatening note — "I will bring a gun to school and shoot all of you" — and slipped it under an assistant principal's office. She said other kids put her up to it.

An 18-year-old in Montana was arrested after posting several threats to "shoot up" his high school. According to court records, he told police he was joking and he was sorry to have scared anybody.

The rash of similar school threats over the last few weeks is genuinely startling. In the Dallas area alone, five teens were arrested for either having guns at school or making threats within 24 hours of the Florida shooting.

Were they dangerous copycats, kids so seriously disturbed they viewed the Florida killer as an inspiration? Or has threatening gun talk and carrying weapons become another titillating source of hallway rumor and internet chat, like sex and drugs? I don't know.

Parents and teachers and principals and cops can't be sure, either, which is why they cannot afford to take any chances.

The likelihood of students being threatened with violence in American schools remains statistically remote, and some studies suggest it's actually on the decline. Plain facts show that children face more danger in their homes than at school.

Which is not particularly reassuring for stressed-out parents, or for a public half-enraged, half-numbed by unhinged gun massacres.

There are some sad, frightening people out there. That the worst of them achieve instant fame is an indictment of our culture. That there are some teenagers out there who find them inspiring is deeply disturbing.

Some teenagers, though, still have it in their heads that this is some kind of social media game. Those are the ones who thought it was a joke or just wanted to impress the other kids. They are trying our patience.

So whether you're a gun owner or not, whether or not you support arming teachers or posting guards and metal detectors at every school door, let's agree that we can tell our kids this: Guns may be many things, but they are not funny.

There's no such thing as a "joke" involving the threat of mass murder. The reality is exactly what those warning signs at the airport say: All threats will be taken seriously.